Zipline trolley systems typically comprise a small trolley that rolls freely along a cable extended between two points. The two points are typically elevated from the ground, with the starting point elevated higher than the finishing point. At the starting point, the user is attached to a trolley (such as the one described in U.S. patent application Ser. No. 12/239,959, the contents of which are hereby incorporated by reference) and sent down the cable. The user is usually attached to the trolley through a number of steel carabiners. At the finishing point, the user is disengaged from the trolley. This system is simple, yet it is not always ensured that the user is placed in a loaded, secure position before the trolley is released from the starting point. This can lead to catastrophic results if improper connections are not detected before the trolley is released.
Some zipline trolley systems finish with a negative grade in order to implement so-called “gravity braking”, wherein the trolley naturally slows down near the finishing point since it has to travel upwards. In such systems, it is necessary to have some means at the finishing point to hold the user when he or she reaches the finishing point in order to prevent the user from rolling back down the cable. In some instances, this would involve a person grabbing and hanging onto the user as he or she approaches the finishing point.
These added procedures at the departure and arrival of every zipline trolley both increase the length of time required for each user to experience the zipline system and complicate the process for starting and ending rides on the zipline trolleys. What is therefore required is a safe and simple system to launch and stop zipline trolleys.